In the packaging of certain chemicals and pharmaceuticals, the manufacturer is often required or desires to provide a considerable amount of information concerning the chemical or pharmaceutical. In the case of chemicals and pharmaceuticals, this is required by government regulations. However, the occasion may also arise, either separate from or in conjunction with government regulations, to provide the doctor, pharmacist or user with instructions on how the product should be used, what the product is, and safety precautions which should be followed in the use of the product. Sometimes the literature, which is generally in the form of folded leaflets, is placed within a box along with the container carrying the chemical or pharmaceutical (referred to as "inserts"). At the same time, in addition to the insert, a primary label must be applied to the outside of the package to remain therewith. This requires a second assembly operation. The placement of leaflets within the box is expensive and a cumbersome operation to perform. Also, it is difficult as well as expensive to insure by later inspection that the proper literature has been inserted in the proper package.
A different approach to solving this problem has developed over the last several years in which the folded literature or leaflets are releasably attached to a face of the container (referred to as "outserts"), either directly to the container itself, or to a base label which, in turn, is secured to the container. The literature may then be removed by the customer. In many of such cases, the portion of the label remaining on the container must carry both an "identification" of the product defined as information such as trademark and/or product identification number, manufacturer and location, etc., as well as certain "statutory information" (defined as lot number and expiration date).
Thus, in order to meet the objectives of such labeling techniques, certain criteria must be met. First of all, the portion of the label which remains after the folded literature is removed must contain both the identification of the product, as well as the statutory information concerning the lot number and expiration date. Further, after the literature leaflet is assembled or affixed to the base label, the indicated area for statutory information concerning lot number and expiration date must be accessible for stamping or printing by the pharmaceutical company at the time the pharmaceutical product is manufactured and packaged. This information must be visible to the consumer in addition to the identification of the product. The folded leaflet portion remains affixed to the label portion until the customer (doctor, pharmacist, consumer) desires its removal. It is critical that the proper literature must be affixed to the proper base label. Finally, all of the above criteria must be accomplished in a manufacturing technique that insures quality and is cost-effective.
Examples of types of labels in the prior art which have addressed some of these criteria are described in U.S. Pat. Nos. 1,273,105 to VanDyke et al.; 4,621,837 to Mack; and 4,323,608 to Denny et al. They are examples of labels which have removable portions thereto.
In U.S. Pat. Nos. 5,207,746 and 5,263,743 to Jones, there are disclosed label constructions whereby the underlying base label is eliminated. The literature, base label, and area for statutory information are all combined into a unitary or integral product. The label constructions as disclosed therein have a bottom identification panel which is adhered to a package by means of a pressure sensitive adhesive coating on its underside. To facilitate handling, the labels are preferably mounted on a silicone coated release liner.
Three methods are known for applying adhesive to a folded leaflet or to the underside of a separate base label as taught in the prior art. An adhesive patch may be applied to the upper surface of a release liner followed by the placement of an outsert or base label thereon. Alternatively, adhesive may be applied to the underside of the bottom panel of the outsert or to the underside of the base label followed by the placement of the outsert or base label onto the release liner. Finally, a continuous layer of adhesive may be applied to the release liner followed by the placement of outserts or base labels thereon.
Each of the above-described methods for applying pressure sensitive adhesive suffers significant drawbacks and limitations. For the first two methods, it is generally necessary to coordinate the application of adhesive and bottom panels or base labels to insure proper registration. If patches of adhesive are used, they must be completely covered by the outserts or base label to avoid binding when the strip of labels is ultimately rewound and unwound. Where adhesive is applied on the underside of the bottom panel or base label, it is necessary to stop applying when an outsert or base label is not in place to avoid applying adhesive over the work area.
If a continuous strip of adhesive is applied to the release liner, either a continuous base stock must be applied or the excess adhesive must be removed prior to placement of the base labels or outserts thereon. If the adhesive is to be removed, then the outsert or base label placement must be coordinated as discussed above with regard to adhesive patches.
Thus, there exists a need for a method for forming pressure sensitive adhesive backed labels mounted on a release liner which does not require an adhesive applying station. Furthermore, there exists a need for such a label construction method wherein the bottom panel of an outsert becomes adhesive coated and is designed to remain with the associated package as a primary label when the remainder of the outsert is removed.